feat: discover jitdump files from MMAP2 records

[DaniPopes]

Jitdump discovery was hardcoded to /tmp/jit-{pid}.dump, missing dumps from LLVM ORC JIT (e.g. revmc, Julia) which write to ~/.debug/jit/*/jit-{pid}.dump.

Instead of searching hardcoded filesystem paths, extract jitdump file paths from MMAP2 records in the perf data, matching how perf inject --jit discovers them via jit_detect().

[greptile-apps]

Greptile Summary

This PR discovers jitdump files from perf MMAP2 records instead of relying only on fixed paths. The main changes are:

• Adds MMAP2-based jitdump path detection for jit-<pid>.dump files.
• Deduplicates discovered jitdump paths per process.
• Restores the legacy /tmp/jit-{pid}.dump fallback for tracked processes.
• Threads the discovered path map through perf symbol and unwind harvesting.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.

Important Files Changed

Filename	Overview
src/executor/wall_time/profiler/perf/jit_dump.rs	Adds the shared jitdump path map, per-process deduplication, legacy /tmp fallback, and path-set harvesting.
src/executor/wall_time/profiler/perf/parse_perf_file.rs	Collects jitdump paths from MMAP2 records and accepts jit-<digits>.dump basenames.
src/executor/wall_time/profiler/perf/mod.rs	Passes discovered jitdump paths through the save pipeline and adds legacy fallback paths before harvesting.
Cargo.toml	Adds indexmap as a direct dependency for stable path deduplication.
Cargo.lock	Updates the lockfile for the direct indexmap dependency.

_{Reviews (2): Last reviewed commit: "fix: dedupe jitdump paths" | Re-trigger Greptile}