Feature: Implement start --watch

[oscar60310]

Description

Provide a flag --watch, -w for start command, which lets the server watch SQL and schemas changes, and restart the server when needed.

Issue ticket number

closes #60

Additional Context

• Watch flag doesn't work in docker CLI, we might need another solution (e.g. polling) for it.

[codecov-commenter]

Codecov Report

Base: 92.73% // Head: 92.53% // Decreases project coverage by -0.20% ⚠️

Coverage data is based on head (1234fdd) compared to base (2a5e525).
Patch coverage: 83.51% of modified lines in pull request are covered.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop      #41      +/-   ##
===========================================
- Coverage    92.73%   92.53%   -0.21%     
===========================================
  Files          229      229              
  Lines         3223     3294      +71     
  Branches       392      404      +12     
===========================================
+ Hits          2989     3048      +59     
- Misses         168      170       +2     
- Partials        66       76      +10     

Flag	Coverage Δ
build	94.87% <ø> (ø)
cli	88.96% <83.51%> (-1.99%)	⬇️
core	93.22% <ø> (ø)
extension-dbt	97.43% <ø> (ø)
extension-debug-tools	98.11% <ø> (ø)
extension-driver-duckdb	100.00% <ø> (ø)
integration-testing	96.15% <ø> (ø)
serve	90.12% <ø> (ø)
test-utility	∅ <ø> (∅)

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Impacted Files	Coverage Δ
packages/cli/src/cli.ts	95.83% <ø> (ø)
packages/cli/src/utils/shutdown.ts	85.71% <75.00%> (-1.79%)	⬇️
packages/cli/src/commands/start.ts	80.30% <80.30%> (-19.70%)	⬇️
packages/cli/src/commands/serve.ts	96.87% <93.33%> (+0.87%)	⬆️
packages/cli/src/commands/build.ts	100.00% <100.00%> (+7.69%)	⬆️

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[kokokuo]

LGTM 👍 👍

[kokokuo]

cc @oscar60310 There is a conflict need to solve.