Ignore secrets and editor files in .gitignore (closes #40)

.gitignore had no secret patterns at all. It is now the org's standard
file, which ignores .env, .env.*, *.pem and *.key and editor and OS
files, plus this repo's /secret (anchored, so internal/secret/ is not
matched), *.log, *.test and settings.local.json. The stale
.cursorrules and coverage.out entries are gone. No tracked file
matches the new patterns.

.dockerignore also leaves out node_modules and ends with a newline.
.git stays in the build context because the build stamps the version
with git describe; .git/config stays excluded.

Model: opus-5-5

TODO.md

@@ -25,6 +25,12 @@ Bring the repo into policy compliance in one commit:
 
 # Completed Steps
 
+- 2026-10-04: `.gitignore` is the org's standard file, which ignores
+  `.env`, `.env.*`, `*.pem` and `*.key` and editor and OS files, plus
+  this repo's `/secret`, `*.log`, `*.test` and `settings.local.json`
+  (https://git.eeqj.de/sneak/secret/issues/40). `.dockerignore` also
+  leaves out `node_modules`; `.git` stays in the build context for the
+  version stamp.
 - 2026-10-04: `secret init` refuses when the default vault exists, and
   `secret vault create NAME` when `NAME` does, with "vault NAME already
   exists", before writing anything. The check is in `vault.CreateVault`,