fix(proofs): align Idris Lang enum with Rust (Chapel not C) — closes #41 (#46)

## Summary

Closes #41 — the Rust `Language` enum and the Idris `Lang` enum both
claimed "49 variants + Unknown" but disagreed on which 49:

| Variant | Rust `src/types.rs` | Idris
`src/abi/PatternCompleteness.idr` |
|---|---|---|
| `Chapel` | ✅ | ❌ (now ✅) |
| `C` | ❌ | ✅ (now ❌) |

Result: the totality theorem `completeScanForAll` was technically
vacuous for `C` (no Rust dispatch existed to verify) and silently
missing coverage for `Chapel`.

## Fix — Option 1 from the issue

Drop `C` from Idris, add `Chapel`. Rationale: `Cpp` already represents
the unified C/C++ analyzer (`analyze_c_cpp` dispatches on `.c` / `.cpp`
/ `.h` / `.hpp` / `.cc` / `.hh`), so there was never a separate `C`
constructor in the Rust source of truth — the original Idris enum had a
phantom constructor.

## Changes

| Location | Change |
|---|---|
| `Lang` data declaration | Remove `C`, add `Chapel` (in new `-- HPC /
parallel` group, mirroring its position in `types.rs`) |
| Header comment | Note that `Cpp` is the C/C++ unified analyzer |
| `analyzerFor` | Drop `analyzerFor C = SpecificAnalyzer`; add
`analyzerFor Chapel = SpecificAnalyzer` |
| `detectorsFor` | 8 lists updated: `[C, Cpp]` → `[Cpp]`
(UncheckedAllocation, UnboundedLoop, UnsafeCode, RaceCondition,
DeadlockPotential, ResourceLeak, InsecureProtocol, HardcodedSecret,
UncheckedError) |

Net diff: -11 / +16 lines, single file.

## Acceptance criteria (from #41)

- [x] `cargo build --release` clean
- [x] `idris2 --check src/abi/PatternCompleteness.idr` — totality OK
- [x] Bijection between the two enumerations:

```
$ comm -23 /tmp/rust-langs /tmp/idris-langs   # in Rust, not Idris
(empty)
$ comm -13 /tmp/rust-langs /tmp/idris-langs   # in Idris, not Rust
(empty)
50 = 50 — match (49 named + Unknown on both sides)
```

## Why this is the right fix

- The Rust enum is the operational source of truth (it's what
`analyze_inner()` actually dispatches against).
- The Idris file is the **mirror** that has to follow.
- `Cpp` analyzer subsumes `.c` files via the unified `analyze_c_cpp`
path, so there is no behavioural regression.
- `Chapel` analyzer is now provably covered by `completeScanForAll`.

## Verification

- [x] `cargo build --release` ✅
- [x] `cargo clippy --all-targets --features signing,http -- -D
warnings` ✅
- [x] `idris2 --check` (totality) ✅
- [x] Signed commit (GPG)

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

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

src/abi/PatternCompleteness.idr

@@ -23,9 +23,12 @@ module PanicAttack.ABI.PatternCompleteness
 
 ||| All 49 programming languages supported by the scanner.
 ||| This MUST stay in sync with src/types.rs Language enum.
+||| Note: Cpp is the C/C++ unified analyzer (analyze_c_cpp dispatches
+||| on .c / .cpp / .h / .hpp / .cc / .hh — there is no separate C
+||| constructor in the Rust enum).
 public export
 data Lang
-  = Rust | C | Cpp | Go | Java | Python | JavaScript | Ruby
+  = Rust | Cpp | Go | Java | Python | JavaScript | Ruby
   -- BEAM family
   | Elixir | Erlang | Gleam
   -- ML family
@@ -44,6 +47,8 @@ data Lang
   | Nickel | Nix
   -- Scripting / data
   | Shell | Julia | Lua
+  -- HPC / parallel
+  | Chapel
   -- Nextgen custom DSLs
   | WokeLang | Eclexia | MyLang | JuliaTheViper | Oblibeny
   | Anvomidav | AffineScript | Ephapax | BetLang | ErrorLang
@@ -70,7 +75,6 @@ data HasAnalyzer : Lang -> Type where
 public export
 analyzerFor : (lang : Lang) -> HasAnalyzer lang
 analyzerFor Rust          = SpecificAnalyzer
-analyzerFor C             = SpecificAnalyzer
 analyzerFor Cpp           = SpecificAnalyzer
 analyzerFor Go            = SpecificAnalyzer
 analyzerFor Java          = SpecificAnalyzer
@@ -106,6 +110,7 @@ analyzerFor Nix           = SpecificAnalyzer
 analyzerFor Shell         = SpecificAnalyzer
 analyzerFor Julia         = SpecificAnalyzer
 analyzerFor Lua           = SpecificAnalyzer
+analyzerFor Chapel        = SpecificAnalyzer
 analyzerFor WokeLang      = SpecificAnalyzer
 analyzerFor Eclexia       = SpecificAnalyzer
 analyzerFor MyLang        = SpecificAnalyzer
@@ -206,24 +211,24 @@ data HasDetector : WPCategory -> Type where
 ||| matching code in analyzer.rs.
 public export
 detectorsFor : (cat : WPCategory) -> HasDetector cat
-detectorsFor UncheckedAllocation  = DetectedBy [C, Cpp]
-detectorsFor UnboundedLoop        = DetectedBy [Rust, C, Cpp, Go, Python, JavaScript]
+detectorsFor UncheckedAllocation  = DetectedBy [Cpp]
+detectorsFor UnboundedLoop        = DetectedBy [Rust, Cpp, Go, Python, JavaScript]
 detectorsFor BlockingIO           = DetectedBy [Rust, Go, Python, JavaScript]
-detectorsFor UnsafeCode           = DetectedBy [Rust, C, Cpp, Zig, Nim, DLang]
+detectorsFor UnsafeCode           = DetectedBy [Rust, Cpp, Zig, Nim, DLang]
 detectorsFor PanicPath            = DetectedBy [Rust, Go, Haskell]
-detectorsFor RaceCondition        = DetectedBy [Rust, C, Cpp, Go]
-detectorsFor DeadlockPotential    = DetectedBy [Rust, C, Cpp, Go]
-detectorsFor ResourceLeak         = DetectedBy [Rust, C, Cpp]
+detectorsFor RaceCondition        = DetectedBy [Rust, Cpp, Go]
+detectorsFor DeadlockPotential    = DetectedBy [Rust, Cpp, Go]
+detectorsFor ResourceLeak         = DetectedBy [Rust, Cpp]
 detectorsFor CommandInjection     = DetectedBy [Python, Ruby, JavaScript, Shell, Elixir, Erlang]
 detectorsFor UnsafeDeserialization = DetectedBy [Python, Ruby, JavaScript, Java]
 detectorsFor DynamicCodeExecution  = DetectedBy [Python, JavaScript, Ruby, Elixir, Shell]
 detectorsFor UnsafeFFI            = DetectedBy [Elixir, Erlang, Haskell, Pony, OCaml, Zig]
 detectorsFor AtomExhaustion       = DetectedBy [Elixir, Erlang]
-detectorsFor InsecureProtocol     = DetectedBy [Rust, C, Cpp, Go, Python, JavaScript, Ruby]
+detectorsFor InsecureProtocol     = DetectedBy [Rust, Cpp, Go, Python, JavaScript, Ruby]
 detectorsFor ExcessivePermissions = DetectedBy [Shell]
 detectorsFor PathTraversal        = DetectedBy [Python, JavaScript, Ruby, Go, Java]
-detectorsFor HardcodedSecret      = DetectedBy [Rust, C, Cpp, Go, Python, JavaScript, Ruby]
-detectorsFor UncheckedError       = DetectedBy [Go, Rust, C, Cpp]
+detectorsFor HardcodedSecret      = DetectedBy [Rust, Cpp, Go, Python, JavaScript, Ruby]
+detectorsFor UncheckedError       = DetectedBy [Go, Rust, Cpp]
 detectorsFor InfiniteRecursion    = DetectedBy [Haskell, PureScript, Scheme, Racket]
 detectorsFor UnsafeTypeCoercion   = DetectedBy [OCaml, Haskell, DLang, Nim]
 detectorsFor ProofDrift           = DetectedBy [Idris, Lean, Agda, Isabelle, Coq, Julia]