Add session log and reflect: API design research session

Session log for 2026-03-29 covering API/LLM security research, agent-runtimes
audit, and review skill creation. Reflected into:
- decisions.md: best-practices topic split, review skills read-only design
- process-lessons.md: background agents for research, Edit context
  disambiguation, best-practices repo location

Pruned 2 old reflected logs (2026-03-17, 2026-03-18).

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

.reflection-state.json

@@ -1,6 +1,6 @@
 {
   "version": 1,
-  "last_run": "2026-03-24T10:36:46Z",
+  "last_run": "2026-03-28T22:15:17Z",
   "processed": {
     "log/2026-03-12.233744.md": "ca482f03914a3b4dec89c2dbf6e0f2e5",
     "log/2026-03-13.100758.md": "65c5b65fdd5984c036f1de53f8c82f2a",
@@ -8,6 +8,8 @@
     "log/2026-03-15.225345.md": "ae9366aed0b4c87ecbbe535e00cb2cb2",
     "log/2026-03-17.103204.md": "56c04b01459f80134e680150c338e9eb",
     "log/2026-03-18.002319.md": "68ab608a650421dcc663fd4ae7131fc9",
-    "log/2026-03-23.123545.md": "2610a8adb53e4b831e3e4b0c1d7cad44"
+    "log/2026-03-23.123545.md": "2610a8adb53e4b831e3e4b0c1d7cad44",
+    "log/2026-03-25.110612.md": "adb467a37c6da84adb5ab5bbf20c773a",
+    "log/2026-03-29.111336.md": "87ad0d241f002605863f66d7fb36c863"
   }
 }