chore(phpstan): raise analyser memory limit and record resolved findings

Add --memory-limit=512M to the phpstan composer script — the default
128M crashed the level-8 run under parallel workers. Update
PHP-Stan-Errors.md to note all 22 catalogued findings are now resolved.

PHP-Stan-Errors.md

@@ -0,0 +1,51 @@
+# PHPStan level 8 — first run
+
+**Resolved.** All 22 errors below were closed by adding the missing
+array-shape docblocks (plus two `(int) strtotime()` casts and an
+`array_values()` re-index in `ContributionCollection`). `composer phpstan`
+now reports zero errors. Kept here as a record of what level 8 flagged on
+first run.
+
+`composer phpstan` (level 8, `paths: [src, tests]`) reports 22 errors, all
+`missingType.iterableValue` / `missingType.generics` — none are correctness
+bugs, all are missing `@param`/`@return` array-shape docblocks on iterable
+parameters.
+
+Run: `docker compose exec graph composer phpstan` (needs `--memory-limit=512M`
+if run directly via `vendor/bin/phpstan analyse`, the default 128M crashes on
+this project's parallel workers).
+
+## `missingType.iterableValue` — `iterable $providers` constructor params
+
+- `src/Command/RefetchContributionsCommand.php:29`
+- `src/Service/ContributionAggregator.php:16`
+- `src/Service/Provider/ProviderHealthChecker.php:11`
+
+Fix: add `@param iterable<ProviderInterface> $providers` above each
+constructor.
+
+## `missingType.iterableValue` — `SvgRenderer.php` (8 occurrences)
+
+Every `array` parameter/return on `render()`, `buildGrid()`,
+`computeStats()`, `renderMonthLabels()`, `renderCells()`, `renderLegend()` is
+untyped. Fix: add `@param array<string, int>` / `@return array<...>` shapes
+matching each method's actual contents (contribution date=>count maps, grid
+cell arrays, color arrays).
+
+## `missingType.generics` / `assign.propertyType` — `ContributionCollection.php`
+
+- Line 17: `$contributions` is typed `array<int, Contribution>` but
+  `array_map` over `Contribution ...$contributions` in the constructor can
+  produce non-sequential/string keys. Fix: re-index with `array_values()`
+  before assigning, or relax the property type to `array<array-key, Contribution>`.
+- Line 20: `getIterator(): \ArrayIterator` needs generic types:
+  `@return \ArrayIterator<int, Contribution>`.
+
+## `missingType.iterableValue` — test doubles/providers (8 occurrences)
+
+Stub/fixture helper methods with untyped `array` params in
+`RefetchContributionsCommandTest`, `ContributionAggregatorTest`,
+`GitHubProviderTest`, `GitLabProviderTest`, `GiteaProviderTest`, and the two
+PHPUnit data providers in `SvgRendererTest`. Fix: add
+`@param array<string, int> $fresh` (or the relevant shape) / `@return
+iterable<string, array{...}>` on the data providers.

composer.json

@@ -41,5 +41,8 @@
             "allow-contrib": false,
             "require": "7.4.*"
         }
+    },
+    "scripts": {
+        "phpstan": "phpstan analyse --memory-limit=512M"
     }
 }