docs(common): fix two pre-existing intra-doc link warnings in telora-common

The `RUSTDOCFLAGS="-D warnings" cargo doc --no-deps --workspace` gate
fails with two pre-existing intra-doc link warnings on `main`
(commit `46f85df`); not introduced by v0.7.2.

**Errors:**

1. `telora-common/src/env.rs:8`:
```
unresolved link to `telora-common`
```
2. `telora-common/src/lib.rs:14`:
```
unresolved link to `env`
```
(ambiguous between module `telora_common::env` and macro `env!`)

**Reproducer:**

```bash
git checkout main
RUSTDOCFLAGS="-D warnings" cargo doc --no-deps --workspace
```

**Fix:** add `mod@` / `crate@` / `macro@` disambiguation to the
intradoc links at the two lines. One-line change per file.

Out of scope for v0.7.2 (already in flight as a dependency bump;
filed separately to avoid scope creep).

Start with the intra-doc links at telora-common/src/env.rs:8 and telora-common/src/lib.rs:14. Run RUSTDOCFLAGS="-D warnings" cargo doc --no-deps --workspace to reproduce the two warnings, then add the specified mod@, crate@, or macro@ disambiguation. Done means the workspace documentation command completes without these warnings.

Written by the indexing model from the issue text.