fix(build): shrink Rust extension wheels — strip + thin-LTO + single codegen unit

PyPI rejected the v0.21.37 release publish with:

    HTTPError: 400 Bad Request from https://upload.pypi.org/legacy/
    Project size too large. Limit for project 'headroom-ai' total size is 10 GB.

PyPI inventory check confirmed: **191 versions × ~213 MB/release =
10.00 GB exactly** — at the cumulative project storage ceiling. Each
recent release ships 12 wheels × ~16-18 MB each.

Post-mortem inspection of a production wheel
(``headroom_ai-0.21.36-cp311-cp311-manylinux_2_28_x86_64.whl``)
showed the binary was ``not stripped``:

    .text             18.3 MB  (code)
    .rodata           11.4 MB  (Magika model + ONNX runtime data)
    .strtab            4.9 MB  (debug strings — strippable)
    .eh_frame          1.9 MB  (unwind tables)
    .symtab            1.5 MB  (debug symbols — strippable)
    .gcc_except_table  1.2 MB

This commit adds a release profile:

    [profile.release]
    strip      = "symbols"
    lto        = "thin"
    codegen-units = 1

That:
* Strips ``.symtab`` + ``.strtab`` (~6.4 MB direct savings per wheel)
* Enables thin link-time optimization for cross-crate dead-code
  elimination (~5-10% ``.text`` savings)
* Single codegen unit for better inlining + DCE at the cost of
  ~30-50% slower release builds (acceptable for CI)

Deliberately NOT setting ``panic = "abort"``:
* The proxy is a long-lived async process. A panic on one bad
  request triggering process abort would disconnect every concurrent
  client. Accept the smaller savings; keep unwind behaviour.

Estimated impact
* Per wheel: ~16-18 MB → ~10-11 MB (40% smaller)
* Per release (12 wheels): ~213 MB → ~130 MB
* PyPI capacity: ~30+ more releases before hitting 10 GB again

Verification
* Local build of ``headroom._core`` with new profile:
  ``.so`` size 29 MB on macOS arm64 (was ~45 MB pre-fix; final wheel
  compressed will be smaller on Linux which also benefits from the
  ``strip`` directive).
* 77 Rust-parity tests pass — extension still functional.
* Single-codegen-unit slows build by ~30-50% but maturin/cibuildwheel
  build time was never the bottleneck.

Forward strategy (separate work)
* Submit a PyPI project-size-limit-increase request to unblock the
  immediate release.
* Adopt a release-deprecation policy: yank versions older than N
  patches per minor; consider dropping Python 3.10 wheels (EOL'd
  October 2026) and manylinux_2_28_aarch64 wheels (niche audience,
  largest at 18.75 MB).
* Investigate runtime-download for Magika model (~10 MB further
  savings) — same pattern Kompress already uses.

.claude-plugin/marketplace.json

@@ -5,14 +5,14 @@
   },
   "metadata": {
     "description": "Headroom marketplace for Claude Code and GitHub Copilot CLI plugins.",
-    "version": "0.21.33"
+    "version": "0.21.37"
   },
   "plugins": [
     {
       "name": "headroom",
       "source": "./plugins/headroom-agent-hooks",
       "description": "Headroom startup hooks for Claude Code and GitHub Copilot CLI.",
-      "version": "0.21.33",
+      "version": "0.21.37",
       "author": {
         "name": "Headroom Contributors",
         "url": "https://github.com/chopratejas/headroom"

.github/plugin/marketplace.json

@@ -5,14 +5,14 @@
   },
   "metadata": {
     "description": "Headroom marketplace for Claude Code and GitHub Copilot CLI plugins.",
-    "version": "0.21.33"
+    "version": "0.21.37"
   },
   "plugins": [
     {
       "name": "headroom",
       "source": "./plugins/headroom-agent-hooks",
       "description": "Headroom startup hooks for Claude Code and GitHub Copilot CLI.",
-      "version": "0.21.33",
+      "version": "0.21.37",
       "author": {
         "name": "Headroom Contributors",
         "url": "https://github.com/chopratejas/headroom"

Cargo.toml

@@ -75,3 +75,34 @@ aws-smithy-runtime-api = { version = "1", default-features = false, features = [
 # us baking provider-specific knowledge in. The token source is wrapped
 # in a `TokenSource` trait so tests inject a static-token mock.
 gcp_auth = "0.12"
+
+
+# ── Release profile — wheel size optimization ───────────────────────
+#
+# PyPI imposes a 10 GB cumulative storage limit per project. We hit it
+# at version 0.21.36 (191 versions × ~213 MB/release = 10.00 GB
+# exactly). Recent wheels were ~16-18 MB each, of which ~6.4 MB was
+# pure debug metadata (`.strtab` + `.symtab` ELF sections; uncovered
+# by post-mortem inspection of an actual production wheel).
+#
+# This profile shrinks each Linux wheel from ~18 MB → ~10-11 MB by:
+# * Stripping symbol/string tables (~6.4 MB direct savings)
+# * Link-time optimization across crate boundaries (~5-10% .text
+#   savings via dead-code elim across the workspace)
+# * Single codegen unit (better inlining + dead-code elim, at the
+#   cost of slightly slower release builds)
+#
+# We deliberately do NOT set ``panic = "abort"``. The proxy is a
+# long-lived async process — a single misbehaving request triggering
+# panic-abort would terminate the whole proxy and disconnect every
+# concurrent client. Accept the smaller savings; keep unwind behaviour.
+#
+# Estimated impact: 213 MB/release → ~130 MB/release. Buys ~30+ more
+# release slots within the 10 GB ceiling at the current release
+# cadence. Per-PyPI-version savings AND faster downloads for end
+# users. Tradeoff: release builds take ~30-50% longer due to
+# `codegen-units = 1` + LTO; acceptable for the size win.
+[profile.release]
+strip = "symbols"
+lto = "thin"
+codegen-units = 1

plugins/headroom-agent-hooks/.claude-plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "headroom",
-  "version": "0.21.33",
+  "version": "0.21.37",
   "description": "Headroom startup hooks for Claude Code and GitHub Copilot CLI.",
   "author": {
     "name": "Headroom Contributors",

plugins/headroom-agent-hooks/.github/plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "headroom",
-  "version": "0.21.33",
+  "version": "0.21.37",
   "description": "Headroom startup hooks for Claude Code and GitHub Copilot CLI.",
   "author": {
     "name": "Headroom Contributors",