chore: tighten gitignore, align README stack, formalize D-010 (Ansible)

- .gitignore: add Keycloak/Mythic/Fernet secret patterns (pfx, p12, token, kdbx,
  credentials.json, secrets.json, service-account*.json), MSVC artifacts
  (lib, exp, idb, ilk, tlog), dedup dist/build/ between Python and Node blocks.
- README.md: align Storage line on H38 (testcontainers Postgres for Postgres-
  specific behavior, incl. unit tests of audit log / RBAC / write-only role).
- README.md: align Deploy line on D-007/D-010 — Docker + Ansible playbook,
  reverse proxy explicitly out-of-Mimic.
- README.md: add proprietary internal use notice.
- CHANGELOG.md: convert markdown link to inline URL (no dangling reference).
- tasks/spec-decisions.md: add D-010 (Ansible for deployment playbook).

Addresses code-reviewer M1/M2/M3 + N2/N3/N4/N6 on commit 047583e.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -4,6 +4,13 @@
 .env.*.local
 *.pem
 *.key
+*.pfx
+*.p12
+*.token
+*.kdbx
+credentials.json
+secrets.json
+service-account*.json
 
 # Python
 __pycache__/
@@ -25,8 +32,6 @@ build/
 
 # Node / Frontend
 node_modules/
-dist/
-build/
 .vite/
 coverage/
 .eslintcache
@@ -40,6 +45,11 @@ test-results/
 *.o
 *.obj
 *.pdb
+*.lib
+*.exp
+*.idb
+*.ilk
+*.tlog
 
 # IDE
 .vscode/