feat(compiler): list literals, typed compound assignment, file:line diagnostics

- `[a, b, c]` list literals (E_LIST → emit_list); static_type learns
  slice-element, `new T`, list, string and literal kinds
- `x op= y` lowers through the same path as `x = x op y` (emit_bin_vals):
  fixed `*=`/`/=` use the Q16.16 64-bit paths, string `+=` concatenates,
  int→long widens; unary `-` keeps a fixed operand's type (arith_ty)
- one `unescape()` table for "strings", 'chars' and `interpolation`;
  `'\''`, `'\\'`, `'\"'` no longer read as 0; unterminated char literals
  and unexpected characters are errors instead of silently skipped
- every diagnostic is `file:line: error: msg` (g_parse_file / g_err_file,
  Node.file + Node.line set by node()); tok_desc() in expectation errors;
  duplicate `function` names and unknown `phase` names are reported in
  source terms (phase_id used to default unknown phases to Overlay)
- interpolation holes skip braces inside string literals
- hand-IR preludes move from the user `@fn_` prefix to `@lp_` so a user
  `is_ws` / `str_eq` / `path_join` no longer collides at link time
- `@ClearColor(expr)` accepts any constant expression; `Os.pid()` added
  (docs page + inventory); `str_starts()` in support/str
- main.ludic: `else if` flag ladder, char literals, stale script comments
- examples/lang/operators.ludic covers all of the above; os.ludic covers
  Os.pid; docs pages for Os.pid and the Overlay phase; ten changesets
- reseeded: selfhost/ludicc.seed.ll is the new compiler's own fixpoint

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tools/ci/forgejo_release.py

@@ -1,107 +0,0 @@
-#!/usr/bin/env python3
-"""Create a Forgejo release and attach build artifacts.
-
-    forgejo_release.py <tag> <body-file> <assets-dir>
-
-Reads the access token from $FORGEJO_TOKEN. `x release --publish` calls this
-after it has pushed the tag; it is the one piece of the release flow that speaks
-HTTP, which the Ludic task runner cannot do yet (a native Http client is issue
-#6). Python stdlib only — no third-party deps — matching the docgen tooling.
-
-Idempotent-ish: if the release for <tag> already exists it is reused, and each
-asset in <assets-dir> is uploaded (a duplicate name is skipped, not fatal).
-"""
-import json
-import os
-import sys
-import urllib.request
-import urllib.error
-
-API = "https://git.workshopsoft.io/api/v1/repos/workshopsoft/ludic"
-
-
-def token():
-    t = os.environ.get("FORGEJO_TOKEN", "").strip()
-    if not t:
-        sys.exit("forgejo_release: FORGEJO_TOKEN is not set")
-    return t
-
-
-def api(method, path, tok, data=None, headers=None, raw=False):
-    url = API + path
-    h = {"Authorization": "token " + tok}
-    body = None
-    if data is not None and not raw:
-        h["Content-Type"] = "application/json"
-        body = json.dumps(data).encode()
-    elif raw:
-        body = data
-        h.update(headers or {})
-    req = urllib.request.Request(url, data=body, headers=h, method=method)
-    with urllib.request.urlopen(req) as r:
-        return r.getcode(), json.loads(r.read().decode() or "null")
-
-
-def get_release_by_tag(tag, tok):
-    try:
-        _, rel = api("GET", "/releases/tags/" + tag, tok)
-        return rel
-    except urllib.error.HTTPError as e:
-        if e.code == 404:
-            return None
-        raise
-
-
-def main():
-    if len(sys.argv) != 4:
-        sys.exit(__doc__)
-    tag, body_file, assets_dir = sys.argv[1], sys.argv[2], sys.argv[3]
-    tok = token()
-
-    body = ""
-    if os.path.exists(body_file):
-        with open(body_file, encoding="utf-8") as fh:
-            body = fh.read()
-
-    rel = get_release_by_tag(tag, tok)
-    if rel is None:
-        _, rel = api("POST", "/releases", tok, {
-            "tag_name": tag,
-            "name": tag,
-            "body": body,
-            "draft": False,
-            "prerelease": tag.startswith("v0."),
-        })
-        print("created release", tag, "id", rel["id"])
-    else:
-        print("release", tag, "already exists (id %s); uploading assets" % rel["id"])
-
-    rid = rel["id"]
-    existing = {a["name"] for a in (rel.get("assets") or [])}
-    if os.path.isdir(assets_dir):
-        for name in sorted(os.listdir(assets_dir)):
-            if name in existing:
-                print("  skip (exists):", name)
-                continue
-            path = os.path.join(assets_dir, name)
-            if not os.path.isfile(path):
-                continue
-            with open(path, "rb") as fh:
-                blob = fh.read()
-            boundary = "----ludicrelease7f3b2a"
-            payload = (
-                ("--%s\r\n" % boundary)
-                + ('Content-Disposition: form-data; name="attachment"; filename="%s"\r\n' % name)
-                + "Content-Type: application/octet-stream\r\n\r\n"
-            ).encode() + blob + ("\r\n--%s--\r\n" % boundary).encode()
-            code, _ = api(
-                "POST", "/releases/%s/assets?name=%s" % (rid, name), tok,
-                data=payload, raw=True,
-                headers={"Content-Type": "multipart/form-data; boundary=" + boundary},
-            )
-            print("  uploaded:", name, "(HTTP %d)" % code)
-    print("done:", API + "/releases/tag/" + tag)
-
-
-if __name__ == "__main__":
-    main()