[Epic] Multi-project collaboration: one year in

[jtcohen6]

Bugs and quality-of-life improvements, collected and prioritized based on feedback from dbt Cloud customers and community members, now that "dbt Mesh" has been out in the world for 6+ months — and thousands are using its constructs in production.

### P0 - must
- [ ] https://github.com/dbt-labs/dbt-core/issues/10116
- [ ] https://github.com/dbt-labs/dbt-core/issues/8987
- [ ] https://github.com/dbt-labs/dbt-core/issues/10134
- [ ] https://github.com/dbt-labs/dbt-core/issues/7442
- [ ] https://github.com/dbt-labs/dbt-core/issues/11034

### P1 - should
- [ ] https://github.com/dbt-labs/dbt-core/issues/9340
- [ ] https://github.com/dbt-labs/dbt-core/issues/9339
- [ ] https://github.com/dbt-labs/dbt-core/issues/8266
- [ ] https://github.com/dbt-labs/dbt-core/issues/8062
- [ ] https://github.com/dbt-labs/dbt-core/issues/11201

### P2 - could
- [ ] https://github.com/dbt-labs/dbt-core/issues/8951
- [ ] https://github.com/dbt-labs/dbt-core/issues/8986
- [ ] https://github.com/dbt-labs/dbt-core/issues/8248
- [ ] https://github.com/dbt-labs/dbt-core/issues/5410
- [ ] https://github.com/dbt-labs/dbt-core/issues/10834

### revisit, refine, prioritize
- [ ] https://github.com/dbt-labs/dbt-core/issues/7432
- [ ] https://github.com/dbt-labs/dbt-core/issues/7759

[jaklan]

#5410 should be definitely a must - as described in the issue, it's completely breaking the monorepo usage of dbt

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