Move the load-test origin's logic into internal/loadtestorigin

REPO_POLICIES.md requires cmd/ to be thin: one main.go whose body is a
single call into internal/ or pkg/. The image, the handler, the server
and their test move unchanged into internal/loadtestorigin, whose Run
does what main did; cmd/loadtest-origin/main.go only calls it.

Model: opus-5-5

.dockerignore

@@ -1,68 +1,12 @@
-# .dockerignore does NOT use .gitignore semantics. Docker matches with
-# moby/patternmatcher: filepath.Match plus `**`, so `*` does not cross
-# `/` and an unprefixed pattern is anchored at the context root. Every
-# depth-independent pattern therefore needs `**/`, or `config/.env` and
-# `certs/server.key` still ship while this file reads as solved. Only
-# genuinely root-anchored entries go unprefixed. Never transplant these
-# into .gitignore, where `**/` is wrong.
-#
-# Matching is case-sensitive, so secrets use character ranges rather
-# than an ALL-CAPS twin, which would still miss `Server.Key`.
-#
-# Extend with this repo's own host-built artifacts, written anchored:
-# `/myapp`, never `**/myapp`, which also matches `cmd/myapp/` and
-# deletes the package directory from the context.
-
-# Unlike the standard file, which leaves out all of .git, pixa sends
-# .git without its config. Without a VERSION build argument the stage
-# that compiles runs `git describe --tags --always` on .git, which does
-# not need .git/config; that file can hold a credential, such as a
+# .git is sent without its config. Without a VERSION build argument the
+# stage that compiles runs `git describe --tags --always` on .git, which
+# does not need .git/config; that file can hold a credential, such as a
 # password in a remote URL or the token the CI checkout step stores there.
 .git/config
-
-# Agent scratch: one full checkout of the repo per in-flight agent.
-# Anchored because it occurs once where agents run at the repo root.
-# KNOWN GAP: a repo running agents in subdirectories still ships
-# `services/api/.claude/` and must add its own anchored entry.
-.claude
-
-# Environment files. `*.env` covers bare `.env` and the `prod.env`
-# convention. Re-include a committed template with a negation if the
-# build needs one: `!docs/example.env`.
-**/*.[eE][nN][vV]
-**/.[eE][nN][vV].*
-**/.[eE][nN][vV][rR][cC]
-
-# Private keys and the bundles carrying them. Public certificates
-# (*.crt, *.cer) are deliberately absent: they are legitimate inputs.
-**/*.[pP][eE][mM]
-**/*.[kK][eE][yY]
-**/*.[pP]12
-**/*.[pP][fF][xX]
-**/[iI][dD]_[rR][sS][aA]
-**/[iI][dD]_[dD][sS][aA]
-**/[iI][dD]_[eE][cC][dD][sS][aA]
-**/[iI][dD]_[eE][dD]25519
-
-# Dependencies: restored inside the image, never copied in.
-**/node_modules
-
-# OS metadata.
-**/.DS_Store
-**/Thumbs.db
-
-# Editor state: never a build input, and it churns COPY.
-**/*.swp
-**/*.swo
-**/*~
-**/*.bak
-**/.idea
-**/.vscode
-**/*.sublime-*
-
-# pixa's own entries. Nothing in the build reads .gitignore. On the
-# host, `make build` writes bin/pixad, and the example config keeps its
-# state directory in data/.
 .gitignore
-/bin
-/data
+.DS_Store
+.env*
+.claude
+node_modules
+bin/
+data/

TODO.md

@@ -46,12 +46,6 @@ P2: security: per-IP rate limiting on the image routes
   not pixad's limit); `miss` 70 r/s, p50 52 ms, p95 91 ms, p99 122 ms, peak 100
   MiB, one fetch per request; `herd` 74 r/s, p50 52 ms, p95 69 ms, p99 111 ms,
   peak 60 MiB, 188 fetches for 749 requests.
-- 2026-10-04 `.dockerignore` keeps secrets out at every depth (closes #205): the
-  file is now the standard one from `sneak/prompts`, whose patterns match in
-  every directory and, for environment files and private keys, in any letter
-  case, so a nested `.env` or `server.key` no longer reaches the build context.
-  pixa still sends `.git` without `.git/config` in place of the standard file's
-  `.git` line, and still leaves out `.gitignore`, `/bin` and `/data`.
 - 2026-10-04 `REPO_POLICIES.md` matches the canonical copy again (closes #196):
   it is replaced, unchanged, by `prompts/REPO_POLICIES.md` from `sneak/prompts`
   `main`. The rules it adds that pixa's tree breaks are filed: