feat: lifetime elision, tooling CI, registry, and LSP locals

Ship the QUALITY_PLAN stretch from ownership through ecosystem: C.1
lifetime elision (bootstrap + selfhost), bux fmt/test/doc CI hooks,
stdlib goldens, package registry (bux search/add), and LSP 0.4
position-sensitive locals with inferred let types. Full-tree format
pass plus Map/Set remove double-free fix.

bootstrap/fmt.nim

@@ -0,0 +1,106 @@
+## fmt.nim — Indentation-based Bux source formatter (bootstrap).
+## Mirrors selfhost `src/fmt.bux`: re-indent by brace depth, preserve content.
+
+import std/[strutils, os, algorithm]
+
+proc isInStringOrComment(line: string, pos: int): bool =
+  ## Simplified: track `//`, `"..."`, and `'...'` up to `pos`.
+  var inString = false
+  var inChar = false
+  var inComment = false
+  var i = 0
+  while i < pos and i < line.len:
+    let c = line[i]
+    let n = if i + 1 < line.len: line[i + 1] else: '\0'
+    if inComment:
+      inc i
+      continue
+    if c == '/' and n == '/':
+      inComment = true
+      inc i
+      continue
+    if c == '"' and not inChar:
+      inString = not inString
+    if c == '\'' and not inString:
+      inChar = not inChar
+    inc i
+  return inString or inChar or inComment
+
+proc countBraceDelta(line: string): int =
+  var delta = 0
+  for i in 0 ..< line.len:
+    if isInStringOrComment(line, i):
+      continue
+    let c = line[i]
+    if c == '{':
+      inc delta
+    elif c == '}':
+      dec delta
+  return delta
+
+proc formatSource*(source: string): string =
+  ## Re-indent each non-empty line to 4 spaces × brace depth.
+  ## Idempotent: formatting a clean file is a no-op.
+  var sb: string
+  var indent = 0
+  # Nim's splitLines leaves a trailing "" when the source ends with '\n'.
+  # Drop that artifact so we don't accumulate blank lines on re-format.
+  var lines = source.splitLines(keepEol = false)
+  if source.len > 0 and source.endsWith('\n') and lines.len > 0 and lines[^1].len == 0:
+    lines.setLen(lines.len - 1)
+  for line in lines:
+    let trimmed = line.strip(leading = true, trailing = false)
+    if trimmed.len == 0:
+      sb.add('\n')
+      continue
+
+    let delta = countBraceDelta(trimmed)
+    let firstChar = trimmed[0]
+    if firstChar == '}':
+      dec indent
+      if indent < 0:
+        indent = 0
+
+    for _ in 0 ..< indent:
+      sb.add("    ")
+    sb.add(trimmed)
+    sb.add('\n')
+
+    if firstChar != '}':
+      indent = indent + delta
+    else:
+      # Net delta after the initial decrease for a leading `}`
+      indent = indent + delta + 1
+      if indent < 0:
+        indent = 0
+
+  return sb
+
+proc formatFile*(path: string, checkOnly: bool): tuple[ok: bool, changed: bool, msg: string] =
+  ## Format `path` in place, or only check if reformatting would change it.
+  if not fileExists(path):
+    return (false, false, "file not found: " & path)
+  let source = readFile(path)
+  let formatted = formatSource(source)
+  if formatted == source:
+    return (true, false, "")
+  if checkOnly:
+    return (true, true, "would reformat")
+  try:
+    writeFile(path, formatted)
+    return (true, true, "formatted")
+  except CatchableError as e:
+    return (false, false, e.msg)
+
+proc collectBuxFiles*(root: string): seq[string] =
+  ## Collect `.bux` files: single file, or recursive directory walk.
+  result = @[]
+  if fileExists(root) and root.endsWith(".bux"):
+    result.add(root)
+    return
+  if not dirExists(root):
+    return
+  for path in walkDirRec(root):
+    if path.endsWith(".bux"):
+      result.add(path)
+  result.sort(system.cmp)