fix: bug: generator emits invalid env var name FORGE_BOT_USER_<service>^^ when service name contains hyphen (#852)

Acceptance items 1-4 landed previously: the primary compose emission
(FORGE_BOT_USER_*) was fixed in #849 by re-keying on forge_user via
`tr 'a-z-' 'A-Z_'`, and the load-project.sh AGENT_* Python emitter was
normalized via `.upper().replace('-', '_')` in #862. Together they
produce `FORGE_BOT_USER_DEV_QWEN2` and `AGENT_DEV_QWEN2_BASE_URL` for
`[agents.dev-qwen2]` with `forge_user = "dev-qwen2"`.

This patch closes acceptance item 5 — the defence-in-depth warn-and-skip
in load-project.sh's two export loops. Hire-agent's up-front reject is
the primary line of defence (a validated `^[a-z]([a-z0-9]|-[a-z0-9])*$`
agent name can't produce a bad identifier), but a hand-edited TOML can
still smuggle invalid keys through:

- `[mirrors] my-mirror = "…"` — the `MIRROR_<NAME>` emitter only
  upper-cases, so `MY-MIRROR` retains its dash and fails `export`.
- `[agents."weird name"]` — quoted TOML keys bypass the bare-key
  grammar entirely, so spaces and other disallowed shell chars reach
  the export loop unchanged.

Before this change, either case would abort load-project.sh under
`set -euo pipefail` — the exact failure mode the original #852
crash-loop was diagnosed from. Now each loop validates `$_key` against
`^[A-Za-z_][A-Za-z0-9_]*$` and warn-skips offenders so siblings still
load.

- `lib/load-project.sh` — regex guard + WARNING on stderr in both
  `_PROJECT_VARS` and `_AGENT_VARS` export loops.
- `tests/lib-load-project.bats` — two regressions: dashed mirror key,
  quoted agent section with space. Both assert (a) the load does not
  abort and (b) sane siblings still load.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/load-project.sh

@@ -85,8 +85,22 @@ if mirrors:
 # environment.  The TOML carries host-perspective values (localhost, /home/admin/…)
 # that would break container API calls and path resolution.  Skip overriding
 # any env var that is already set when running inside the container.
+#
+# #852 defence: validate that $_key is a legal shell identifier before
+# `export`.  A hand-edited TOML can smuggle in keys that survive the
+# Python emitter but fail `export`'s identifier rule — e.g.
+# `[mirrors] my-mirror = "..."` becomes `MIRROR_MY-MIRROR` because the
+# MIRROR_<NAME> emitter only upper-cases, it does not dash-to-underscore.
+# Without this guard `export "MIRROR_MY-MIRROR=…"` returns non-zero, and
+# under `set -euo pipefail` in the caller the whole file aborts — which
+# is how the original #852 crash-loop presented.  Warn-and-skip keeps
+# the rest of the TOML loadable.
 while IFS='=' read -r _key _val; do
   [ -z "$_key" ] && continue
+  if ! [[ "$_key" =~ ^[A-Za-z_][A-Za-z0-9_]*$ ]]; then
+    echo "WARNING: load-project: skipping invalid shell identifier from TOML: $_key" >&2
+    continue
+  fi
   if [ "${DISINTO_CONTAINER:-}" = "1" ] && [ -n "${!_key:-}" ]; then
     continue
   fi
@@ -152,8 +166,16 @@ for name, config in agents.items():
 " "$_PROJECT_TOML" 2>/dev/null) || true
 
   if [ -n "$_AGENT_VARS" ]; then
+    # #852 defence: same warn-and-skip guard as the main loop above.  The
+    # Python emitter already normalizes dashed agent names (#862), but a
+    # quoted TOML section like `[agents."weird name"]` could still produce
+    # an invalid identifier.  Fail loudly but keep other agents loadable.
     while IFS='=' read -r _key _val; do
       [ -z "$_key" ] && continue
+      if ! [[ "$_key" =~ ^[A-Za-z_][A-Za-z0-9_]*$ ]]; then
+        echo "WARNING: load-project: skipping invalid shell identifier from [agents.*]: $_key" >&2
+        continue
+      fi
       export "$_key=$_val"
     done <<< "$_AGENT_VARS"
   fi