Document DS component constructor validation and reduce duplication

[Copilot]

Documents the DS component constructor validation introduced in PRs #7082 and #7085. Starting with bnd 7.3.0, component classes must have either a public no-arg constructor or a public @Activate-annotated constructor. Non-static inner classes now fail validation correctly.

Changes

• docs/_chapters/200-components.md: Added "Component Class Requirements" section with constructor validation rules, valid/invalid examples, and inner class requirements (104 lines)

• docs/_instructions/_ext/dsannotations.md: Added brief validation overview linking to detailed section (reduced duplication by 16 lines)

• docs/_chapters/920-faq.md: Added FAQ entry "Why does bnd require a public no-arg constructor for my DS component?" with concise answer linking to detailed section (reduced duplication by 58 lines)

Error Example

The DS component class {className} must declare a public no-arg constructor, 
or a public constructor annotated with @Activate.

Valid Patterns

// Implicit no-arg constructor
@Component
public class MyComponent { }

// Constructor injection
@Component
public class MyComponent {
    @Activate
    public MyComponent(BundleContext context) { }
}

// Static inner class
@Component
public class Outer {
    @Component
    public static class Inner { }
}

Total duplication eliminated: 74 lines. Detailed content consolidated in 200-components.md with cross-references from dsannotations.md and 920-faq.md.

Original prompt

Based on issue #7078 and PRs #7082 and #7085 please suggest what should be added to related docs pages such as:

• docs/_chapters/200-components.md
• docs/instructions/dsannotations_options.html
• docs/instructions/dsannotations.html

and maybe other places like FAQ docs/chapters/920-faq.html

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[chrisrueger]

@kwin I asked for some help with the docs for recent DS related PR: #7078 , #7082 and #7085

Would be great if you have a look to if it makes sense. Feel free to suggest improvements / changes.

@peterkir FYI