docs: remove docs/adr; move the decisions that survive to the docs and the code

AGENTS.md

@@ -33,8 +33,8 @@ Every module under `modern_di/` is named for what it does; read it. What a singl
   template per resolver shape and `exec`'d with the factory's constants as globals; the other provider
   types compile to closures. A new provider type must add a branch here or `compile_resolver` raises.
   Nothing in the template calls a helper on the hot path: the per-node frame budget is the point, and
-  `test_resolve_costs_exactly_one_resolver_frame_per_node` says why. Overrides are compiled in
-  (`docs/adr/0030-exec-template-resolver.md`): an override change drops the compiled resolvers.
+  `test_resolve_costs_exactly_one_resolver_frame_per_node` says why. Overrides are compiled in: an
+  override change drops the compiled resolvers.
 - `exceptions.py` owns **every message and every glyph**. A raise site passes structured facts, never
   formatting; the class renders its own f-string and sets a `docs_slug` (its page under
   `docs/troubleshooting/`, enforced by `tests/test_docs_slug_census.py`). Add a message, a glyph, or a
@@ -79,5 +79,5 @@ a sibling test may be the one that trips.
 - **Issues and specs** — GitHub Issues on `modern-python/modern-di`, via `gh`:
   [`docs/agents/issue-tracker.md`](docs/agents/issue-tracker.md)
 - **Triage labels** — the five canonical roles: [`docs/agents/triage-labels.md`](docs/agents/triage-labels.md)
-- **Domain docs** — single-context, `CONTEXT.md` + `docs/adr/`: [`docs/agents/domain.md`](docs/agents/domain.md)
+- **Domain docs** — single-context, `CONTEXT.md`; public choices on the design-decisions page, internal ones in `docs/adr/`: [`docs/agents/domain.md`](docs/agents/domain.md)
 - **Cutting a release** (maintainers) — [`docs/agents/release.md`](docs/agents/release.md)

docs/adr/0001-resolver-hot-path-generated-source.md

@@ -0,0 +1,19 @@
+# The resolve hot path is generated source, one frame per node
+
+A `Factory` resolver is generated from a source template specialised to the factory's resolver
+shape and `exec`'d with the factory's constants as its globals. Nothing on the hot path calls a
+shared helper, and `test_resolve_costs_exactly_one_resolver_frame_per_node` enforces it. Every
+all-Python single-copy design was measured first and lost 25-80% on a chain: folding the arity
+ladder into one closure costs even for the branches not taken (closure size is paid on every call
+on CPython 3.12+), and a shared `build()` or `call()` helper is a frame per node. So the
+duplication the template removes cannot be removed with functions. Overrides are compiled in for
+the same reason: an override change drops the compiled resolvers instead of every resolver
+checking the overrides registry.
+
+## Consequences
+
+- The hot path is a string. `ruff`, `ty` and coverage do not see it; the shape-enumeration test
+  in `tests/test_resolver_compiler.py` is the gate for a template / namespace mismatch.
+- One code object per shape, not per provider. Per provider is 20-30% faster on chains (call sites
+  stay monomorphic) but costs ~70 µs of `compile()` per provider, which a suite building a
+  container per test pays per test.