feat(learn): excerpts and the example store (decision-engine 6.1)

learn/excerpt.py: the labelled function at its pin as numbered lines, bounded
(80 lines / 4,000 chars for candidates, 40 / 2,000 for memory examples),
centred on focus lines; advisory ids anywhere and comments with security
wording (labels.security_reason, multilingual) become <redacted>; owner,
owner/name, path and commit ids are replaced; a delta unit appends the
base->head diff (<= 40 lines). C/C++ and other brace languages without a
repo-facts declaration pattern use a brace matcher (346 c_cpp pair rows
had no excerpt without it).

learn/examples.py + `ousast learn memory build`: label + feature record +
excerpt -> `example` rows (no rationale), excerpts as content-addressed
blobs; refuses origin: user and sources outside sources.toml (exit 2);
conditional labels skipped; exit 2 when >10% of a source's recorded
candidates have no excerpt. A fixed side that was read but no longer
declares the labelled function is counted apart (absent_fixed_side): a
label defect, not an unread clone.

plane/memory.py: `example` in KINDS; put_blob/get_blob/blob_names on the
MemoryStore base, so FileStore and MinioStore share them (tested on both,
MinIO through the fake object client).

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo

benchmarks/measurements/2026-09-08-module-audit.json

@@ -1,7 +1,7 @@
 {
-  "modules": 143,
+  "modules": 146,
   "counts": {
-    "load_bearing": 136,
+    "load_bearing": 139,
     "standalone_capability": 7
   },
   "orphaned": [],
@@ -352,6 +352,9 @@
       "reason": "reachable from gate, map_gate, pair_gate or the CLI",
       "importers": [
         "cli",
+        "learn.cli",
+        "learn.examples",
+        "learn.excerpt",
         "learn.features",
         "learn.roles",
         "plane.tasks.features",
@@ -359,11 +362,36 @@
         "plane.tasks.roles"
       ]
     },
+    {
+      "module": "learn.cli",
+      "classification": "load_bearing",
+      "reason": "reachable from gate, map_gate, pair_gate or the CLI",
+      "importers": [
+        "cli"
+      ]
+    },
+    {
+      "module": "learn.examples",
+      "classification": "load_bearing",
+      "reason": "reachable from gate, map_gate, pair_gate or the CLI",
+      "importers": [
+        "learn.cli"
+      ]
+    },
+    {
+      "module": "learn.excerpt",
+      "classification": "load_bearing",
+      "reason": "reachable from gate, map_gate, pair_gate or the CLI",
+      "importers": [
+        "learn.examples"
+      ]
+    },
     {
       "module": "learn.features",
       "classification": "load_bearing",
-      "reason": "imported by plane.tasks.features",
+      "reason": "reachable from gate, map_gate, pair_gate or the CLI",
       "importers": [
+        "learn.excerpt",
         "plane.tasks.features"
       ]
     },
@@ -372,13 +400,16 @@
       "classification": "load_bearing",
       "reason": "reachable from gate, map_gate, pair_gate or the CLI",
       "importers": [
-        "cli"
+        "cli",
+        "learn.cli",
+        "learn.examples",
+        "learn.excerpt"
       ]
     },
     {
       "module": "learn.roles",
       "classification": "load_bearing",
-      "reason": "imported by learn.features, plane.tasks.features, plane.tasks.roles",
+      "reason": "reachable from gate, map_gate, pair_gate or the CLI",
       "importers": [
         "learn.features",
         "plane.tasks.features",
@@ -706,6 +737,7 @@
         "improve",
         "improve.evolve",
         "improve.memory",
+        "learn.examples",
         "learn.labels",
         "model.candidates",
         "pair_gate",
@@ -719,6 +751,8 @@
       "importers": [
         "cli",
         "improve.memory",
+        "learn.cli",
+        "learn.examples",
         "plane.egress",
         "plane.engine_alerts",
         "plane.generate",
@@ -792,6 +826,8 @@
       "reason": "harnessx-removal Req 6.1/6.4: the memory store (file, MinIO), ingest and fact reuse; `ousast plane remember`",
       "importers": [
         "improve.memory",
+        "learn.cli",
+        "learn.examples",
         "plane.generate",
         "plane.tasks.loop",
         "plane.tasks.remember"
@@ -828,6 +864,7 @@
       "reason": "ai-service-plane Req 4.1: the task entrypoint package the runner imports by name; runner integration pending (task 3)",
       "importers": [
         "cli",
+        "learn.excerpt",
         "learn.features",
         "learn.labels",
         "learn.roles",
@@ -884,6 +921,7 @@
       "classification": "load_bearing",
       "reason": "ai-service-plane Req 5.1/5.2: source-only functions and callers per file; runner integration pending",
       "importers": [
+        "learn.excerpt",
         "learn.features",
         "learn.labels",
         "learn.roles",