fix: return Result from record constructors instead of panicking (closes #26)

[Dani-giron]

Summary

SimpleNumberRecord::create, SimpleTlshRecord::create and GenericJsonRecord::create build records from untrusted strings (e.g. a line read from a dataset file), but used unwrap() on the parse step. Verified empirically: feeding malformed input to the pre-fix logic panics the process (exit code 101), aborting a whole ingestion run over a single bad entry.

Also: insert() used println! to warn about a duplicate key instead of the tracing crate already used elsewhere in the codebase.

Changes

• src/datalayer/error.rs (new): RecordError (InvalidNumber, InvalidTlshHash), each variant carrying the offending input string. Implements Display and std::error::Error.
• src/datalayer/record.rs: all three constructors now return Result<Self, RecordError> instead of panicking.
• src/controllers/apotheosis.rs: insert() uses tracing::warn! instead of println!.
• src/bin/test_numbers.rs, test_tlsh.rs: updated to the new signature with .expect(...) (internally generated / pre-validated data, not user input).

Scope note: dump()/load() still return Box<dyn std::error::Error> rather than a typed error. Left out of this PR since it overlaps with #24 (open, rewrites load()); a unified error type across persistence and record construction is a natural follow-up once that merges.

Test plan

• tests/record_construction.rs (new, 4 tests): malformed input returns Err with the offending input in the message; valid input returns Ok.
• cargo test, cargo clippy --all-targets --all-features -- -D warnings, rustfmt --check all pass locally.
• Manually verified pre-fix behavior: same malformed input against the old unwrap()-based logic panics (exit code 101); post-fix returns Err and the process continues.

Closes #26