feat(headroom): activate/uninstall extras + fix interpreter detection

- find interpreter next to headroom binary so extras/version read correctly
- add on/off toggle to activate [code]/[ml] via proxy restart
- add uninstall action + live install log progress + ~1GB confirm modal

src/lib/headroom/detect.js

@@ -9,7 +9,7 @@ export const HEADROOM_COMPRESSION_EXTRAS = ["code", "ml"];
 
 // Marker packages that each extra pulls in. Detected from `pip list --format=json`
 // so one call can answer both the installed version and active extras.
-const EXTRA_MARKERS = {
+export const EXTRA_MARKERS = {
   code: ["tree-sitter", "tree-sitter-language-pack"],
   ml: ["torch", "huggingface-hub"],
 };
@@ -64,11 +64,33 @@ export function findHeadroomBinary() {
 }
 
 // Find a Python interpreter >= 3.10 (headroom-ai requires it). Returns null if none.
-// On Windows, `python3` and `python` can point at different envs. Prefer the
-// first candidate that can also see the installed `headroom-ai` package so the
+// `python3`, `python3.13`, `python` can point at different envs on any OS. Prefer
+// the interpreter that can also see the installed `headroom-ai` package so the
 // dashboard probes and install action operate on the same interpreter as the CLI.
+// Falls back to the first version-eligible candidate when headroom-ai is not yet
+// installed anywhere (needed for the initial install).
+// Interpreters to probe, most specific first: the python next to the headroom
+// binary (guaranteed to have headroom-ai), then full paths from EXTRA_BINS, then
+// bare names resolved via PATH.
+function pythonCandidates() {
+  const list = [];
+  const bin = findHeadroomBinary();
+  if (bin) {
+    const dir = path.dirname(bin);
+    const names = IS_WIN ? ["python.exe", "python3.exe"] : ["python3", "python3.13", "python"];
+    for (const n of names) list.push(path.join(dir, n));
+  }
+  for (const dir of EXTRA_BINS) {
+    if (!dir) continue;
+    for (const n of PYTHON_CANDIDATES) list.push(path.join(dir, IS_WIN ? `${n}.exe` : n));
+  }
+  list.push(...PYTHON_CANDIDATES);
+  return list;
+}
+
 export function findPython310() {
-  for (const candidate of PYTHON_CANDIDATES) {
+  let fallback = null;
+  for (const candidate of pythonCandidates()) {
     try {
       const ver = execSync(`${candidate} --version`, {
         stdio: ["ignore", "pipe", "ignore"],
@@ -79,7 +101,7 @@ export function findPython310() {
       if (!match) continue;
       const [major, minor] = [parseInt(match[1], 10), parseInt(match[2], 10)];
       if (!(major > MIN_VERSION[0] || (major === MIN_VERSION[0] && minor >= MIN_VERSION[1]))) continue;
-      if (!IS_WIN) return candidate;
+      if (!fallback) fallback = candidate;
       try {
         execFileSync(candidate, ["-m", "pip", "show", "headroom-ai"], {
           stdio: ["ignore", "pipe", "ignore"],
@@ -89,13 +111,13 @@ export function findPython310() {
         });
         return candidate;
       } catch {
-        // Keep scanning on Windows until an interpreter sees headroom-ai.
+        // Keep scanning until an interpreter that sees headroom-ai is found.
       }
     } catch {
       // candidate not present, try next
     }
   }
-  return null;
+  return fallback;
 }
 
 // Probe whether a Headroom proxy is reachable at the given URL by hitting /health.

src/lib/headroom/process.js

@@ -2,11 +2,12 @@ import fs from "fs";
 import path from "path";
 import { spawn } from "child_process";
 import { DATA_DIR } from "@/lib/dataDir.js";
-import { findHeadroomBinary, findPython310, HEADROOM_COMPRESSION_EXTRAS, getInstalledHeadroomExtras } from "./detect.js";
+import { findHeadroomBinary, findPython310, HEADROOM_COMPRESSION_EXTRAS, EXTRA_MARKERS, getInstalledHeadroomExtras } from "./detect.js";
 
 const HEADROOM_DIR = path.join(DATA_DIR, "headroom");
 const PID_FILE = path.join(HEADROOM_DIR, "proxy.pid");
 const LOG_FILE = path.join(HEADROOM_DIR, "proxy.log");
+const INSTALL_LOG_FILE = path.join(HEADROOM_DIR, "install.log");
 const DEFAULT_PORT = 8787;
 const STARTUP_TIMEOUT_MS = 8000;
 
@@ -41,7 +42,17 @@ export function getManagedPid() {
   return pid && isPidAlive(pid) ? pid : null;
 }
 
-export async function startHeadroomProxy({ port = DEFAULT_PORT } = {}) {
+// Build proxy CLI flags for the active compression extras. `[code]` (AST
+// compression) is off by default in headroom → pass --code-aware to turn it on;
+// `[ml]` (Kompress) is on by default → pass --disable-kompress to turn it off.
+function extrasProxyArgs({ codeAware, kompress } = {}) {
+  const args = [];
+  if (codeAware) args.push("--code-aware");
+  if (kompress === false) args.push("--disable-kompress");
+  return args;
+}
+
+export async function startHeadroomProxy({ port = DEFAULT_PORT, codeAware = false, kompress = true } = {}) {
   const safePort = Number(port) > 0 && Number(port) < 65536 ? Number(port) : DEFAULT_PORT;
   const binary = findHeadroomBinary();
   if (!binary) {
@@ -57,7 +68,8 @@ export async function startHeadroomProxy({ port = DEFAULT_PORT } = {}) {
   // spawn stdio requires fd numbers, not WriteStream objects.
   const outFd = fs.openSync(LOG_FILE, "a");
 
-  const child = spawn(binary, ["proxy", "--port", String(safePort)], {
+  const args = ["proxy", "--port", String(safePort), ...extrasProxyArgs({ codeAware, kompress })];
+  const child = spawn(binary, args, {
     stdio: ["ignore", outFd, outFd],
     detached: true,
     windowsHide: true,
@@ -118,6 +130,25 @@ export function stopHeadroomProxy() {
   }
 }
 
+// Stop the managed proxy (if any), wait for the pid to die, then start again
+// with the given flags. Used when toggling active extras that require a restart.
+export async function restartHeadroomProxy(opts = {}) {
+  const pid = getManagedPid();
+  if (pid) {
+    try { process.kill(pid, "SIGTERM"); } catch { /* already gone */ }
+    // Wait up to ~3s for graceful exit, force-kill if still alive.
+    for (let i = 0; i < 30 && isPidAlive(pid); i++) {
+      await new Promise((r) => setTimeout(r, 100));
+    }
+    if (isPidAlive(pid)) {
+      try { process.kill(pid, "SIGKILL"); } catch { /* already gone */ }
+      await new Promise((r) => setTimeout(r, 300));
+    }
+    clearPid();
+  }
+  return startHeadroomProxy(opts);
+}
+
 export function getHeadroomLogTail(maxLines = 200) {
   try {
     if (!fs.existsSync(LOG_FILE)) return "";
@@ -153,7 +184,8 @@ export async function installHeadroomExtras(extras = []) {
   const args = ["-m", "pip", "install", "--upgrade", spec];
 
   ensureDir();
-  const outFd = fs.openSync(path.join(HEADROOM_DIR, "install.log"), "a");
+  // Truncate ("w") so the log reflects only the current install for live progress.
+  const outFd = fs.openSync(INSTALL_LOG_FILE, "w");
   const child = spawn(py, args, {
     stdio: ["ignore", outFd, outFd],
     windowsHide: true,
@@ -175,3 +207,54 @@ export async function installHeadroomExtras(extras = []) {
     });
   });
 }
+
+// Uninstall the marker packages that back a single extra (e.g. `ml` → torch,
+// huggingface-hub). `headroom-ai` base and the `proxy` extra are never removed.
+export async function uninstallHeadroomExtras(extras = []) {
+  const requested = Array.isArray(extras) ? extras.filter((e) => HEADROOM_COMPRESSION_EXTRAS.includes(e)) : [];
+  const py = findPython310();
+  if (!py) {
+    const err = new Error("Python >= 3.10 not found");
+    err.code = "NO_PYTHON";
+    throw err;
+  }
+  const pkgs = [...new Set(requested.flatMap((e) => EXTRA_MARKERS[e] || []))];
+  if (pkgs.length === 0) {
+    const err = new Error("No valid extras to remove");
+    err.code = "INVALID_EXTRAS";
+    throw err;
+  }
+  const args = ["-m", "pip", "uninstall", "-y", ...pkgs];
+
+  ensureDir();
+  const outFd = fs.openSync(INSTALL_LOG_FILE, "w");
+  const child = spawn(py, args, {
+    stdio: ["ignore", outFd, outFd],
+    windowsHide: true,
+    env: { ...process.env },
+  });
+
+  return new Promise((resolve, reject) => {
+    child.once("error", (e) => { fs.closeSync(outFd); reject(e); });
+    child.once("exit", (code) => {
+      fs.closeSync(outFd);
+      if (code === 0) {
+        const status = getInstalledHeadroomExtras(py);
+        resolve({ success: true, code, removed: pkgs, extras: requested, ...status });
+      } else {
+        const err = new Error(`pip uninstall exited with code=${code} — see headroom/install.log`);
+        err.code = "UNINSTALL_FAILED";
+        reject(err);
+      }
+    });
+  });
+}
+
+// Read the tail of the install/uninstall log for live progress in the UI.
+export function getInstallLogTail(maxLines = 15) {
+  try {
+    if (!fs.existsSync(INSTALL_LOG_FILE)) return "";
+    const lines = fs.readFileSync(INSTALL_LOG_FILE, "utf8").split(/\r?\n/).filter(Boolean);
+    return lines.slice(-maxLines).join("\n");
+  } catch { return ""; }
+}