… reuse stats in mangler builds (#23352)

## What

Fix three allocation problems in the semantic rebuilds performed by the minify/mangle paths, found while auditing the compiler pipeline's scoping rebuilds.

## Details

- **`Semantic::stats` reported `nodes: 0` after node-less builds.** It read `self.nodes.len()`, which is empty when the builder runs in ancestry mode (`with_build_nodes(false)` — the compiler pipeline default). `Semantic` now tracks `node_count` (from `AstNodeStore::node_count`, the source of truth in both modes) and `stats()` returns it. The mangler build inside `Minifier::build` previously received `nodes: 0` and grew the `AstNodes` store from zero capacity by repeated doubling; it now pre-allocates correctly.
- **`Minifier::build` with `compress: None` fed the mangler `Stats::default()`.** All-zero stats are worse than no stats: they skip the `Stats::count` fallback *and* reserve zero capacity for every table. Stats are now threaded as `Option<Stats>` and only passed when the compress phase produced them; the mangle-only path falls back to the counting pass and sizes correctly.
- **`Mangler::build` always re-counted the AST.** Added `Mangler::with_stats`, and `CompilerInterface::mangle` now receives the stats from the initial semantic build, so the mangler's internal semantic rebuild skips its full-AST counting traversal.

Output is unchanged — stats only affect pre-allocation.

## Note

`CompilerInterface::mangle` gains a `stats: Stats` parameter — a breaking change for external implementors that override it (same shape as the `compress` change in #23153).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

### 💥 BREAKING CHANGES

- 7a76cd3 estree: [**BREAKING**] Make whether to include TS fields a
runtime option (#23574) (overlookmotel)
- e7b6b68 estree: [**BREAKING**] `ESTree` config use methods not consts
(#23573) (overlookmotel)

### 🚀 Features

- 556cc6d data_structures: Add `CodeBuffer::as_str` method (#23571)
(overlookmotel)
- 38c4b06 parser: Add friendly error for adjacent JSX elements (#23378)
(sapphi-red)
- 53509a8 minifier: Treeshake pure typed arrays and Set/Map array
literals (#23469) (Dunqing)
- 09762d9 minifier: Inline const value for read-only vars (#22593)
(Dunqing)

### 🐛 Bug Fixes

- 20375f9 react_compiler: Keep imports referenced only by a computed key
(#23586) (Boshen)
- 31bfd9b minifier: Keep Object introspection calls on a possible Proxy
(#23483) (Dunqing)
- 837a395 parser: Treat a line comment after ':' as leading, not
trailing (#23515) (Dunqing)
- e409fe0 minifier: Keep `new Map`/`WeakSet`/`WeakMap` with a string
argument (#23470) (Dunqing)
- ae02b4e ci/parser: Use `minimal` for vitest reporter (#23457)
(camc314)

### ⚡ Performance

- cf24329 mangler: Compile slot sort once instead of per CAPACITY
(#23577) (Boshen)
- 4058a6a parser: Reduce code bloat from verify_modifiers
monomorphization (#23576) (Boshen)
- 053b0c1 estree: Remove pointless `mem::take` (#23572) (overlookmotel)
- dfb52b6 transformer: Pre-size statement vecs in TS enum & namespace
lowering (#23516) (Yunfei He)
- 970e09a minifier: Compute template-literal inline checks in a single
pass (#23467) (Yunfei He)
- 3170c0e semantic,mangler,minifier: Fix `Semantic::stats` node count
and reuse stats in mangler builds (#23352) (Boshen)
- d1fa6e0 minifier: Evaluate ternary branches once in
minimize_conditional_expression (#23479) (Yunfei He)
- 3fa8051 transformer: Pre-size JSX props vec to attribute count
(#23466) (Yunfei He)
- 488b382 react_compiler: Borrow binding names in prefilter instead of
allocating (#23471) (Yunfei He)
- bcb3894 minifier: Incremental scoping refresh, delete
LiveUsageCollector (#23197) (Dunqing)

### 📚 Documentation

- f68641e data_structures: Improve docs on safety contract (#23575)
(overlookmotel)

Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>