chore: pmboard runtime cleanup (pm-board R17, R15)

Delete tracked stale runtime marker: .pm/gitea-url (config now lives in .pm/board.yaml).
Add top-level gitea_url key to .pm/board.yaml (from the old marker value).
Add .gitignore block for .pm runner output and legacy runtime files (never tracked).

Implements pm-board R17 (no state files; config-only board) and R15 (gitea_url/site_url links).

.gitignore

@@ -1,2 +1,9 @@
 __pycache__/
 *.pyc
+
+# pm-board runner output and legacy runtime files (never tracked)
+.pm/runs.jsonl
+.pm/address-state.json
+.pm/address-history.jsonl
+.pm/feedback-state.json
+.pm/outbox.md

.pm/board.yaml

@@ -1,3 +1,4 @@
+gitea_url: "https://git.jajahome.duckdns.org/omp/rsi"
 requirements:
   - id: R1
     title: Jev research summary

.pm/gitea-url

@@ -1 +0,0 @@
-https://git.jajahome.duckdns.org/omp/rsi