store: Fix stale loadRelated results while blocks are queued (<> all and exclusion of unrelated queued writes)

[madumas]

Fixes #6726.

Queue::get_derived combines queued changes with a database read at the block before the queue, and hides the queued keys from that read through excluded_keys. Two defects let older database versions through, so loadRelated could return children that a queued block had removed or moved to another parent. Whether that happened depended on writer timing.

Two commits, which can be reviewed separately:

1. store: Exclude every listed key in FindDerivedQuery: id != any($excluded) → id <> all($excluded). With two or more keys, the old predicate excluded nothing.
2. store: Exclude queued keys no longer related in get_derived: in effective_ops, a queued write that is no longer related to the parent now excludes its key instead of being dropped. A newer queued version always supersedes the database row, whether or not it is still related.

Tests: four store tests in store/test-store/tests/postgres/writable.rs (get_derived_pending_*). They hold the writer, call get_derived while a block is queued, then flush. Without the fixes:

• two_removals and removal_and_creation fail without commit 1;
• parent_change fails without commit 2;
• one_removal is a control that passed before.

The existing get_derived_batch and get_derived_nobatch still pass.

Notes:

• The empty array is still guarded (if !self.excluded_keys.is_empty()).
• <> all(array) has the same planner characteristics as != any(array).
• Commit 2 excludes every queued key of the queried entity type, so the bind array is somewhat larger on big batches.
• Behaviour change: for subgraphs that call loadRelated on children moved or removed while blocks are queued, results and therefore PoIs can differ from released versions. The current behaviour is timing-dependent, so this probably deserves a release note.

Checks run locally on this branch: cargo fmt --all -- --check, cargo clippy --all-targets (no warnings), cargo check --release, cargo test -p graph-store-postgres --lib, cargo test -p test-store --test postgres, and the workspace unit tests.