conformance: record common-lisp blocker (per-suite counters + preloads)

Classified migratable-in-kind (SX suites over epoch, not a foreign runner)
but blocked on driver feature gaps: 8 distinct per-suite counter variable
name pairs and per-suite preload chains, neither supported by MODE=counters
(single global counter + fixed preloads) nor MODE=dict (load-time counter
collisions across suites). Baseline 305/0 across 12 suites. Did not migrate;
conformance.sh left untouched. Driver unchanged (out of per-iteration scope).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

plans/agent-briefings/conformance-loop.md

@@ -85,7 +85,7 @@ Blocked with specifics and move to the next candidate next iteration.
 
 ## Checklist
 
-- [ ] common-lisp
+- [!] common-lisp — blocked: needs per-suite counter names + per-suite preloads (see Blocked)
 - [ ] erlang
 - [ ] feed
 - [ ] forth
@@ -100,8 +100,30 @@ Blocked with specifics and move to the next candidate next iteration.
 
 ## Progress log (newest first)
 
-- (none yet)
+- 2026-06-07 — common-lisp: classified migratable-in-kind (SX suites over epoch) but
+  BLOCKED on driver feature gaps. Baseline `bash lib/common-lisp/conformance.sh` =
+  305 passed / 0 failed across 12 suites (3 — evaluator/geometry/mop-trace — already
+  emit 0/0, a pre-existing extraction quirk). Not a foreign runner, so not Excluded.
+  Did NOT migrate (parity unachievable under current modes); left conformance.sh
+  untouched. See Blocked. Driver left unchanged (out of strict per-iteration scope).
 
 ## Blocked
 
-- (none yet)
+- **common-lisp** — the shared driver's two modes can't reproduce its 305/0 breakdown:
+  1. **Per-suite counter variable names.** Old script reads 8 distinct pairs across
+     its 12 suites: `cl-test-pass`/`cl-test-fail` (read, lambda, eval), `passed`/`failed`
+     (conditions, clos), `demo-passed`/`demo-failed`, `parse-passed`/`parse-failed`,
+     `debugger-passed`/`debugger-failed`, `geo-passed`/`geo-failed`,
+     `mop-passed`/`mop-failed`, `macro-passed`/`macro-failed`, `stdlib-passed`/`stdlib-failed`.
+     `MODE=counters` supports only one global `COUNTERS_PASS`/`COUNTERS_FAIL`.
+  2. **Per-suite preload chains.** Each suite loads a different file set
+     (e.g. read: `reader.sx`; clos: `runtime.sx clos.sx`; macros: `reader parser eval loop`).
+     `MODE=counters` loads one fixed `PRELOADS` set before every suite.
+  `MODE=dict` also fails: these tests run at *load* time mutating globals (no
+  `-tests-run!` runner fns), and dict mode loads all suites into one session — the
+  shared `passed`/`failed` counters used by both conditions and clos would collide.
+  **Unblock path (driver enhancement, deferred — out of this loop's per-iteration scope):**
+  extend `MODE=counters` with optional per-suite counter names and per-suite preloads
+  in the `SUITES` entry format (backward-compatible with the `name:file` shape haskell
+  uses). Same gap likely affects other remaining candidates; worth a one-time driver
+  change before resuming migrations.